Multistability and Transient Response of the Greenland Ice Sheet to Anthropogenic CO2 Emissions

• Published in: Geophysical Research Letters
• Main Authors: Höning, Dennis, Willeit, Matteo, Calov, Reinhard, Klemann, Volker, Bagge, Meike, Ganopolski, Andrey
• Format: Article in Journal/Newspaper
• Language: English
• Published: AGU (American Geophysical Union) 2023
• Subjects: Greenland; Ice Sheet
• Online Access: https://oceanrep.geomar.de/id/eprint/58672/; https://oceanrep.geomar.de/id/eprint/58672/1/Geophysical%20Research%20Letters_2023_Hoening.pdf; https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2022GL101827; https://doi.org/10.1029/2022GL101827

Understanding the future fate of the Greenland Ice Sheet (GIS) in the context of anthropogenic CO2 emissions is crucial to predict sea level rise. With the fully coupled Earth system model of intermediate complexity CLIMBER-X, we study the stability of the GIS and its transient response to CO2 emissions over the next 10 Kyr. Bifurcation points exist at global temperature anomalies of 0.6 and 1.6 K relative to pre-industrial. For system states in the vicinity of the equilibrium ice volumes corresponding to these temperature anomalies, mass loss rate and sensitivity of mass loss to cumulative CO2 emission peak. These critical ice volumes are crossed for cumulative emissions of 1,000 and 2,500 GtC, which would cause long-term sea level rise by 1.8 and 6.9 m respectively. In summary, we find tipping of the GIS within the range of the temperature limits of the Paris agreement. Key Points Bifurcation points exist at global mean temperature anomalies of 0.6 and 1.6 K relative to pre-industrial Mass loss rate and sensitivity to cumulative CO2 emission peak near the equilibrium ice volumes belonging to these temperature anomalies Substantial long-term mass loss of the Greenland ice sheet for cumulative emissions larger than 1,000 Gt carbon